Detectors
Soon Will Be No Match for NIST-Tuned Radar Guns

Theres
no worse feeling than being waved off the road by a police officer
with a radar gun in his hand. Unless youre that officer
trying to enforce the speed limit with traditional equipment.

Across-the-road
Doppler photo radarsaimed across a thoroughfare instead
of parallel to or alongside itare increasingly being used
for measuring vehicle speeds on the nations highways. These
devices provide distinct advantages over older radar guns: easier
concealment, better differentiation between vehicles, automated
identification of offenders using complementary photographic equipment,
and best of all for officersnothing that will triggger a
radar detector. Unfortunately, the radars currently also require
frequent calibration to ensure their accuracy.

At
the request of the National Highway Traffic Safety Administration,
the National Institute of Standards and Technology (NIST) has
developed calibrator/simulator units that will certify the performance
and accuracy of across-the-road traffic radars. The units soon
will undergo field tests.

The
calibrator/simulator units are self-contained with software that
simulates vehicles from motorcycles to trucks over speeds from
24 to 193 kilometers per hour (15 to 120 miles per hour) with
an expected accuracy of plus or minus 2 kilometers per hour (1
mile per hour). The calibrator units are reliable, simple in design
and should be inexpensive when manufactured in quantity.

NIST
Chocolate Standard Raises the Bar on Accuracy

Chocoholics,
rejoice. Now theres a way to know more precisely than
ever how much fat (and other constituents) are in chocolate
and similar foods.

The National
Institute of Standards and Technology (NIST) has issued Standard
Reference Material (SRM) 2384, Baking Chocolate, which has been
characterized with state-of-the-art measurement methods to show
how much fat, protein, carbohydrates, individual fatty acids,
elements, vitamins and other components it contains. It is part
of a series of food-matrix SRMs that can be used by food processors
to validate analytical methods and for quality assurance when
assigning values to products with similar compositions.

The baking
chocolate SRM is the first standard to contain a high proportion
of fatmore than 50 percent. A high-fat food standard has
been identified as a priority by manufacturers. Because of this
high fat content, the new SRM can be analyzed by manufacturers
of chocolate and by quality assurance labs of companies that
produce other types of fatty products, such as black olives
and potato chips. This SRM also is the first to have values
assigned for catechins (which, as antioxidants, may help protect
the body against damage associated with age-related diseases)
and caffeine.

NISTs
food-matrix SRMs will help manufacturers comply with the Food
and Drug Administration labeling requirements.

NIST
Chemists Define and Refine Properties of Plastic Microsystems

There
may well be a plastic biochip in your future, thanks in part to
the National Institute of Standards and Technology (NIST).

Microfluidics
devices, also known as lab-on-a-chip systems, are
miniaturized chemical and biochemical analyzers that one day may
be used for quick, inexpensive tests in physicians offices.
Most microfluidics devices today are made of glass materials.
Cheaper, disposable devices could be made of plastics, but their
properties are not yet well understood.

NIST
is contributing to the development of these plastic microfluidics.
One study looked at how fluids flowed in plastic microchannels
by tracking fluorescent dye in the fluids. NIST researchers also
developed an easy technique for accurately measuring fluid temperaturesan
important parameter for chemical reactions.

A
third project spawned a method for concentrating and separating
an ionic (charged) substance in solution within microchannels.
The technique concentrates the substance as much as 10,000-fold
or more, making it easier to detect in ultrasmall quantities (nanolitersa
billionth of a literor less).

Finally,
NIST staff designed a novel system to overcome the difficult problem
of slow mixing in microfluidics devices. The mixer consists of
a T-shaped microchannel imprinted in plastic that is modified
with a laser to create a series of slanted wells. The wells speed
the mixing of two streams entering the passage.

NIST
Keeps Users from Getting Burned by Bad Pepper Sprays

Pepper
spray, which irritates the eyes, skin and airways, can temporarily
disable an attacker without the need for physical force or weaponry.
For this reason, police officers increasingly use pepper sprays
in the line of duty. However, the last thing they need to find
out in a dangerous situation is that their spray doesnt
work.

Under
the direction of the Office of Law Enforcement Standards (OLES)
at the National Institute of Standards and Technology (NIST),
researchers at the University of Utah Center for Human Toxicology
are evaluating the amount of oleoresin capsicum (OC, the active
ingredient oil extracted from the cayenne pepper plant) in pepper
sprays and then assessing just how well they live up to claims
of effectiveness.

An
analysis of 10 commercial sprays revealed wide variations in OC
content. The spray with the strongest OC concentration had about
40 times the amount in the weakest spray.

OLES
also is looking at dose response relationships (what levels of
response are evoked by different levels of OC) and evaluating
the specific effects of pepper sprays on the skin.

In
the future, NIST plans to use the data from this project to make
recommendations about standardizing the labeling of pepper sprays
so that consumersespecially those in law enforcementwill
know exactly what they are purchasing.

NISTs
work in this area has been funded by the National Institute of
Justice, the research arm of the U.S. Department of Justice.

New NIST
Booklet Tells How to Short Circuit Surges

You
might think that lightning strikes in the blink of an eye,
but a typical voltage surge in your house as a result of lightning
happens much faster. Although the surge happens quickly, its effectssuch
as computers and other appliances going haywirecan leave
sensitive electrical devices with permanent damage.

The
National Institute of Standards and Technology (NIST) has produced
a new booklet titled Surges Happen! to inform the public about
how to protect their home appliances from this threat.

The
bookletcreated by NISTs Electronics and Electrical
Engineering Laboratoryexplains how and why electrical surges
take place,
and the impact they can have on various appliances. Additionally,
it describes the different classes of surge protectors on the
market and how they work. While the booklet gives consumers useful
information about how to decide which kinds of surge protectors
they need (if any), it is an objective guide that does not endorse
any particular product or manufacturer.

Consumers
may obtain free copies of the booklet by faxing a request to (301)
926-1630 or sending an e-mail message to inquiries@nist.gov.
Internet users may download a copy in Adobe Acrobat format from
www.nist.gov/practiceguides.

Time
& Frequency

Need
the Time or Need to Know About Time ... Go to NIST!

If
only the World Wide Web had been around in 1970, the musical group
Chicago would have never asked the question Does anyone
really know what time it is? All the band would have needed
is to go to the National Institute of Standards and Technology
(NIST) Web site at www.boulder.nist.gov/timefreq.

From
the home page of NISTs Time and Frequency Division, one
can access the NIST Internet time service (www.boulder.nist.gov/timefreq/service/its.htm)
and download software for synchronizing computer clocks to Coordinated
Universal Time via the Internet. The NIST Internet Time Service
now receives 450 million hits per day, a figure that is expected
to grow by 8 percent per month.

Many of these requests come from commercial and industrial users
who need accurate time signals to synchronize point-of-sale terminals,
validate the processing of transactions or control automated metering
and billing equipment. In fact, the National Association of Securities
Dealers requires that member transactions be time-stamped with
a clock whose accuracy is traceable to NIST.

Along
with getting accurate time, visitors to the Time and Frequency
Web site also may take A Walk Through Time at http://physics.nist.gov/GenInt/Time/time.html.
This illustrated description of the evolution of timekeeping recently
has been revised and updated. It describes how humanity has developed
a multitude of ways to measure and keep track of the passage of
time.

The
walk culminates in todays atomic clocks, including
the NIST-F1, accurate to within one second in nearly 20 million
years. Written for a general audience, A Walk Through Time
includes a bibliography for further exploration of the topic.

In
1972, NIST evaluated the noise levels of 13 tractor-trailer trucks
and a delivery van. The trucks were operated in range of two series
of microphonesone set inside the vehicles to register what
a driver would hear and the other outside to determine what other
drivers and residents along the road would experience. The trucks
produced between 75 and 95 decibels, prompting the Occupational
Safety and Health Administration to establish guidelines to prevent
hearing loss.

An
anechoic (sound absorbing) chamber was built at NISTs Gaithersburg,
Md., facility in the 1970s. The room was lined with large fiberglass
wedges arranged in a pattern that absorbed more than 99 percent
of the sound originating in it. Among the items tested in the
chamber were hearing aids, microphones, loudspeakers and hearing
protectors used on firing ranges. In 1976, the Julliard String
Quartet played inside the chamber to test the acoustical properties
of their 17th and 18th century instruments.

In
direct contrast to the anechoic chamber, a reverberation chamber
in operation at NISTs Maryland campus during the 1970s reflected
about 95 percent of the sound striking its concrete walls. The
acoustic absorption of architectural materials and the intensity
of sound emitted by machinery were two of the evaluations conducted
in the reverberation room.